The present invention relates to a method for procuring instructions regarding a target subscriber in a telecommunication network, as well as source and destination nodal points for this.
Due to a subscriber""s moving, in a telecommunication network it is repeatedly necessary for the subscriber to be assigned a new subscriber number because the subscriber can no longer be reached via the old subscriber number of the previous subscriber line of his previous residence, but rather via his new subscriber number at his new residence. The deregulation of the telecommunication market may also have the result that a subscriber who changes his service provider cannot always keep his previous subscriber number. So that a caller who calls the moved subscriber at his previous subscriber numberxe2x80x94and whose call is therefore established to a local switching center of the previous residencexe2x80x94does not try several times in vain to call under the old subscriber number, an announcement is switched on from this local switching center that at least informs the caller that the called subscriber cannot be reached at the dialed subscriber number.
When he calls the old subscriber number, the caller is advantageously also informed of the new subscriber number of the called subscriber. As is known from the particle xe2x80x9cAutomatic, computer-controlled announcement of changed call numbers in conventional switching systemsxe2x80x9d by Dieter Humboldt, employee in the Darmstadt central telephone office, published in the magazine F.I.T.C.E. (January-Febuary. 1977, volume 16, issue no. 1, pp. 1-6, ISSN: 0304-4416), to announce the new subscriber number the local switching center of the previous residence connects the call to a central announcement center which determines the new subscriber number using the previous subscriber number and announces it by means of an automatic speech generation. The announcement is then transmitted from the central announcement center via the local switching center to the caller. In the simplest case, the subscriber line of the caller and the subscriber number that cannot be reached are in the range of operation of the same local switching center, in such a way that besides the local switching center, only the line paths from the caller to the local switching center and on to the central announcement center are loaded by this call and the announcement of the new subscriber number However, the caller will often call from a farther location and then make use of several nodal points and a longer line path, eventually also in the long-distance service range. The author of the aforementioned article therefore points out that the caller can listen to the announcement of a changed subscriber number in long-distance service only for a limited period of time free of charge.
To handle a call to a subscriber unable to be reached at the dialed subscriber number, components of an intelligent network are used in European patent application EP 0 753 975 A2 instead of the central announcement center. When a caller enters a subscriber number at his terminal, the call is established via a source switching center and to a SSP nodal point (SSP=Service switching Point). The SSP nodal point then checks, by means of a call number list, whether the desired subscriber can be reached at the dialed subscriber number or if he has received a new subscriber number. If the desired subscriber has a new subscriber number, the SSP nodal point asks a SCP nodal point (SCP=Service Control Point) for instructions as to how the call should be handled further. According to these instructions, the SSP nodal point establishes either a connection from the caller on to a terminal with the new subscriber number or, using a so-called intelligent processorxe2x80x94this refers to an intelligent peripheralxe2x80x94plays an announcement for the caller that gives information on the new subscriber number. With this method, the SSP nodal point must determine for each call whether the desired subscriber can be reached via the dialed subscriber number. In addition, an updated call number list of changed subscriber numbers must always be available in the SSP nodal point. Since there are typically numerous SSP nodal points in a telecommunication network, a non-negligible expenditure is incurred in maintaining the call number lists.
As an alternative, the aforementioned European patent application proposes to store the call number list in the SCP nodal point. Then, at each call to be further processed, the SSP nodal point must first send the SCP nodal point an inquiry regarding the dialed subscriber number in order to learn whether or not the subscriber number has changed and how to proceed in the case of a changed subscriber number. For most calls, however, the dialed subscriber number is the current subscriber number of the desired subscriber, in such a way that considerable data traffic is created by the regular inquiries to the SCP nodal point.
The technical problem of the invention is to easily further process a call to a target subscriber who cannot be reached with a subscriber number dialed at a terminal.
This technical problem is solved by a method for procuring instructions whereby with the method, by dialing the subscriber number at the source terminal (TSRC), a connection (CON1, CON2) is established from this source terminal (TSRC) via a first nodal point (XSRC)xe2x80x94which can be connected with an intelligent network unit (SCP)xe2x80x94to a second nodal point (XDEST), with the following steps: the second nodal point (XDEST) sends the first nodal point (XSRC) an answer message that the desired subscriber number cannot be reached via the second nodal point (XDEST), the connection (CON1, CON2) on the section (CON2) from the second nodal point (XDEST) to the first nodal point (XSRC) is released, after receiving the answer message, the first nodal point (XSRC) requests instructions from the intelligent network installation (SCP) regarding the target subscriber unable to be reached via the dialed subscriber number, the intelligent network installation (SCP) transmits the requested instructions to the first nodal point (XSRC), if the instructions concern a speech announcement, the first nodal point (XSRC), using the instructions, supplies a speech announcement to the source terminal (TSRC), or if the instructions concern charging for a call to a new subscriber number of the target subscriber unable to be reached via the dialed subscriber number, the first nodal point. (XSRC) executes the instructions for charging.
The invention further comprises a nodal point (XDEST) for procuring instructions regarding a target subscriber in a telecommunication network, whereby the nodal point (XDEST) has means for receiving and means for executing an instruction with which the nodal point (XDEST) is instructed to make a connection from a first nodal point (XSRC) through itself and on to a unit with a subscriber number indicated in the instruction, and whereby the nodal point (XDEST) has means to send the first nodal point an answer message if the unit can no longer be reached via the subscriber number for the nodal point because the subscriber number has been replaced by a new subscriber number, characterized in that the nodal point (XDEST) includes means to insert into the answer message a piece of information that the selected subscriber number can no longer be reached because the subscriber number has been replaced by a new subscriber number.
The invention further includes a nodal point for procuring instructions regarding a target subscriber in a telecommunication network who can no longer be reached via a subscriber number dialed at a source terminal (TSRC), whereby the nodal point (XSRC) has means, when dialing the subscriber number at the source terminal (TSRC), to make a connection (CON1, CON2) from this source terminal (TSRC) through itself and on to at least a second nodal point (XDEST), and whereby the nodal point (XSRC) can be connected with an intelligent network unit (SCP), characterized in that the nodal point (XSRC) includes: means to receive and read an answer message that is sent from the second nodal point (XDEST) when the desired subscriber number cannot be reached via the second nodal point (XDEST); means, after reading the answer message, to send the intelligent network unit (SCP) an inquiry with which instructions are requested regarding the target subscriber unable to be reached via the dialed subscriber number, means to receive the requested instructions from the intelligent network unit (SCP), and if the instructions concern a speech announcement, the nodal point (XSRC) has means to supply, according to the instructions, a speech announcement to the source terminal with a content indicated in the instructions, or if the instructions concern charging for a call to a new subscriber number of the target subscriber unable to be reached via the dialed subscriber number, the nodal point (XSRC) has means to execute the instructions for charging
Further advantageous designs of the invention can be seen from the dependent claims and the description.